1 files changed, 132 insertions, 0 deletions
diff --git a/core/src/main/java/org/elasticsearch/search/fetch/subphase/highlight/HighlightPhase.java b/core/src/main/java/org/elasticsearch/search/fetch/subphase/highlight/HighlightPhase.java
new file mode 100644
index 0000000000..2909e71445
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+++ b/core/src/main/java/org/elasticsearch/search/fetch/subphase/highlight/HighlightPhase.java
@@ -0,0 +1,132 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.elasticsearch.search.fetch.subphase.highlight;
+
+import org.apache.lucene.search.Query;
+import org.elasticsearch.common.component.AbstractComponent;
+import org.elasticsearch.common.regex.Regex;
+import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.index.mapper.DocumentMapper;
+import org.elasticsearch.index.mapper.FieldMapper;
+import org.elasticsearch.index.mapper.KeywordFieldMapper;
+import org.elasticsearch.index.mapper.SourceFieldMapper;
+import org.elasticsearch.index.mapper.StringFieldMapper;
+import org.elasticsearch.index.mapper.TextFieldMapper;
+import org.elasticsearch.search.fetch.FetchSubPhase;
+import org.elasticsearch.search.internal.SearchContext;
+
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+public class HighlightPhase extends AbstractComponent implements FetchSubPhase {
+    private static final List<String> STANDARD_HIGHLIGHTERS_BY_PRECEDENCE = Arrays.asList("fvh", "postings", "plain");
+
+    private final Map<String, Highlighter> highlighters;
+
+    public HighlightPhase(Settings settings, Map<String, Highlighter> highlighters) {
+        super(settings);
+        this.highlighters = highlighters;
+    }
+
+    @Override
+    public void hitExecute(SearchContext context, HitContext hitContext) {
+        if (context.highlight() == null) {
+            return;
+        }
+        Map<String, HighlightField> highlightFields = new HashMap<>();
+        for (SearchContextHighlight.Field field : context.highlight().fields()) {
+            Collection<String> fieldNamesToHighlight;
+            if (Regex.isSimpleMatchPattern(field.field())) {
+                DocumentMapper documentMapper = context.mapperService().documentMapper(hitContext.hit().type());
+                fieldNamesToHighlight = documentMapper.mappers().simpleMatchToFullName(field.field());
+            } else {
+                fieldNamesToHighlight = Collections.singletonList(field.field());
+            }
+
+            if (context.highlight().forceSource(field)) {
+                SourceFieldMapper sourceFieldMapper = context.mapperService().documentMapper(hitContext.hit().type()).sourceMapper();
+                if (!sourceFieldMapper.enabled()) {
+                    throw new IllegalArgumentException("source is forced for fields " +  fieldNamesToHighlight + " but type [" + hitContext.hit().type() + "] has disabled _source");
+                }
+            }
+
+            boolean fieldNameContainsWildcards = field.field().contains("*");
+            for (String fieldName : fieldNamesToHighlight) {
+                FieldMapper fieldMapper = getMapperForField(fieldName, context, hitContext);
+                if (fieldMapper == null) {
+                    continue;
+                }
+
+                // We should prevent highlighting if a field is anything but a text or keyword field.
+                // However, someone might implement a custom field type that has text and still want to
+                // highlight on that. We cannot know in advance if the highlighter will be able to
+                // highlight such a field and so we do the following:
+                // If the field is only highlighted because the field matches a wildcard we assume
+                // it was a mistake and do not process it.
+                // If the field was explicitly given we assume that whoever issued the query knew
+                // what they were doing and try to highlight anyway.
+                if (fieldNameContainsWildcards) {
+                    if (fieldMapper.fieldType().typeName().equals(TextFieldMapper.CONTENT_TYPE) == false &&
+                        fieldMapper.fieldType().typeName().equals(KeywordFieldMapper.CONTENT_TYPE) == false &&
+                        fieldMapper.fieldType().typeName().equals(StringFieldMapper.CONTENT_TYPE) == false) {
+                        continue;
+                    }
+                }
+                String highlighterType = field.fieldOptions().highlighterType();
+                if (highlighterType == null) {
+                    for(String highlighterCandidate : STANDARD_HIGHLIGHTERS_BY_PRECEDENCE) {
+                        if (highlighters.get(highlighterCandidate).canHighlight(fieldMapper)) {
+                            highlighterType = highlighterCandidate;
+                            break;
+                        }
+                    }
+                    assert highlighterType != null;
+                }
+                Highlighter highlighter = highlighters.get(highlighterType);
+                if (highlighter == null) {
+                    throw new IllegalArgumentException("unknown highlighter type [" + highlighterType + "] for the field [" + fieldName + "]");
+                }
+
+                Query highlightQuery = field.fieldOptions().highlightQuery() == null ? context.parsedQuery().query() : field.fieldOptions().highlightQuery();
+                HighlighterContext highlighterContext = new HighlighterContext(fieldName, field, fieldMapper, context, hitContext, highlightQuery);
+
+                if ((highlighter.canHighlight(fieldMapper) == false) && fieldNameContainsWildcards) {
+                    // if several fieldnames matched the wildcard then we want to skip those that we cannot highlight
+                    continue;
+                }
+                HighlightField highlightField = highlighter.highlight(highlighterContext);
+                if (highlightField != null) {
+                    highlightFields.put(highlightField.name(), highlightField);
+                }
+            }
+        }
+        hitContext.hit().highlightFields(highlightFields);
+    }
+
+    private FieldMapper getMapperForField(String fieldName, SearchContext searchContext, HitContext hitContext) {
+        DocumentMapper documentMapper = searchContext.mapperService().documentMapper(hitContext.hit().type());
+        // TODO: no need to lookup the doc mapper with unambiguous field names? just look at the mapper service
+        return documentMapper.mappers().smartNameFieldMapper(fieldName);
+    }
+}